安卓uvc的driver

/* * uvc_driver.c -- USB Video Class driver * * Copyright (C) 2005-2010 * Laurent Pinchart (laurent.pinchart@ideasonboard.com) * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * */ #include <linux/atomic.h> #include <linux/kernel.h> #include <linux/list.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/usb.h> #include <linux/videodev2.h> #include <linux/vmalloc.h> #include <linux/wait.h> #include <linux/version.h> #include <asm/unaligned.h> #include <media/v4l2-common.h> #include "uvcvideo.h" #define DRIVER_AUTHOR "Laurent Pinchart " \ "<laurent.pinchart@ideasonboard.com>" #define DRIVER_DESC "USB Video Class driver" unsigned int uvc_clock_param = CLOCK_MONOTONIC; unsigned int uvc_no_drop_param; static unsigned int uvc_quirks_param = -1; unsigned int uvc_trace_param; unsigned int uvc_timeout_param = UVC_CTRL_STREAMING_TIMEOUT; /* ------------------------------------------------------------------------ * Video formats */ static struct uvc_format_desc uvc_fmts[] = { { .name = "YUV 4:2:2 (YUYV)", .guid = UVC_GUID_FORMAT_YUY2, .fcc = V4L2_PIX_FMT_YUYV, }, { .name = "YUV 4:2:2 (YUYV)", .guid = UVC_GUID_FORMAT_YUY2_ISIGHT, .fcc = V4L2_PIX_FMT_YUYV, }, { .name = "YUV 4:2:0 (NV12)", .guid = UVC_GUID_FORMAT_NV12, .fcc = V4L2_PIX_FMT_NV12, }, { .name = "MJPEG", .guid = UVC_GUID_FORMAT_MJPEG, .fcc = V4L2_PIX_FMT_MJPEG, }, { .name = "YVU 4:2:0 (YV12)", .guid = UVC_GUID_FORMAT_YV12, .fcc = V4L2_PIX_FMT_YVU420, }, { .name = "YUV 4:2:0 (I420)", .guid = UVC_GUID_FORMAT_I420, .fcc = V4L2_PIX_FMT_YUV420, }, { .name = "YUV 4:2:0 (M420)", .guid = UVC_GUID_FORMAT_M420, .fcc = V4L2_PIX_FMT_M420, }, { .name = "YUV 4:2:2 (UYVY)", .guid = UVC_GUID_FORMAT_UYVY, .fcc = V4L2_PIX_FMT_UYVY, }, { .name = "Greyscale 8-bit (Y800)", .guid = UVC_GUID_FORMAT_Y800, .fcc = V4L2_PIX_FMT_GREY, }, { .name = "Greyscale 8-bit (Y8 )", .guid = UVC_GUID_FORMAT_Y8, .fcc = V4L2_PIX_FMT_GREY, }, { .name = "Greyscale 10-bit (Y10 )", .guid = UVC_GUID_FORMAT_Y10, .fcc = V4L2_PIX_FMT_Y10, }, { .name = "Greyscale 12-bit (Y12 )", .guid = UVC_GUID_FORMAT_Y12, .fcc = V4L2_PIX_FMT_Y12, }, { .name = "Greyscale 16-bit (Y16 )", .guid = UVC_GUID_FORMAT_Y16, .fcc = V4L2_PIX_FMT_Y16, }, { .name = "RGB Bayer", .guid = UVC_GUID_FORMAT_BY8, .fcc = V4L2_PIX_FMT_SBGGR8, }, { .name = "RGB565", .guid = UVC_GUID_FORMAT_RGBP, .fcc = V4L2_PIX_FMT_RGB565, }, { .name = "H.264", .guid = UVC_GUID_FORMAT_H264, .fcc = V4L2_PIX_FMT_H264, }, }; /* ------------------------------------------------------------------------ * Utility functions */ struct usb_host_endpoint *uvc_find_endpoint(struct usb_host_interface *alts, __u8 epaddr) { struct usb_host_endpoint *ep; unsigned int i; for (i = 0; i < alts->desc.bNumEndpoints; ++i) { ep = &alts->endpoint[i]; if (ep->desc.bEndpointAddress == epaddr) return ep; } return NULL; } static struct uvc_format_desc *uvc_format_by_guid(const __u8 guid[16]) { unsigned int len = ARRAY_SIZE(uvc_fmts); unsigned int i; for (i = 0; i < len; ++i) { if (memcmp(guid, uvc_fmts[i].guid, 16) == 0) return &uvc_fmts[i]; } return NULL; } static __u32 uvc_colorspace(const __u8 primaries) { static const __u8 colorprimaries[] = { 0, V4L2_COLORSPACE_SRGB, V4L2_COLORSPACE_470_SYSTEM_M, V4L2_COLORSPACE_470_SYSTEM_BG, V4L2_COLORSPACE_SMPTE170M, V4L2_COLORSPACE_SMPTE240M, }; if (primaries < ARRAY_SIZE(colorprimaries)) return colorprimaries[primaries]; return 0; } /* Simplify a fraction using a simple continued fraction decomposition. The * idea here is to convert fractions such as 333333/10000000 to 1/30 using * 32 bit arithmetic only. The algorithm is not perfect and relies upon two * arbitrary parameters to remove non-significative terms from the simple * continued fraction decomposition. Using 8 and 333 for n_terms and threshold * respectively seems to give nice results. */ void uvc_simplify_fraction(uint32_t *numerator, uint32_t *denominator, unsigned int n_terms, unsigned int threshold) { uint32_t *an; uint32_t x, y, r; unsigned int i, n; an = kmalloc(n_terms * sizeof *an, GFP_KERNEL); if (an == NULL) return; /* Convert the fraction to a simple continued fraction. See * http://mathforum.org/dr.math/faq/faq.fractions.html * Stop if the current term is bigger than or equal to the given * threshold. */ x = *numerator; y = *denominator; for (n = 0; n < n_terms && y != 0; ++n) { an[n] = x / y; if (an[n] >= threshold) { if (n < 2) n++; break; } r = x - an[n] * y; x = y; y = r; } /* Expand the simple continued fraction back to an integer fraction. */ x = 0; y = 1; for (i = n; i > 0; --i) { r = y; y = an[i-1] * y + x; x = r; } *numerator = y; *denominator = x; kfree(an); } /* Convert a fraction to a frame interval in 100ns multiples. The idea here is * to compute numerator / denominator * 10000000 using 32 bit fixed point * arithmetic only. */ uint32_t uvc_fraction_to_interval(uint32_t numerator, uint32_t denominator) { uint32_t multiplier; /* Saturate the result if the operation would overflow. */ if (denominator == 0 || numerator/denominator >= ((uint32_t)-1)/10000000) return (uint32_t)-1; /* Divide both the denominator and the multiplier by two until * numerator * multiplier doesn't overflow. If anyone knows a better * algorithm please let me know. */ multiplier = 10000000; while (numerator > ((uint32_t)-1)/multiplier) { multiplier /= 2; denominator /= 2; } return denominator ? numerator * multiplier / denominator : 0; } /* ------------------------------------------------------------------------ * Terminal and unit management */ struct uvc_entity *uvc_entity_by_id(struct uvc_device *dev, int id) { struct uvc_entity *entity; list_for_each_entry(entity, &dev->entities, list) { if (entity->id == id) return entity; } return NULL; } static struct uvc_entity *uvc_entity_by_reference(struct uvc_device *dev, int id, struct uvc_entity *entity) { unsigned int i; if (entity == NULL) entity = list_entry(&dev->entities, struct uvc_entity, list); list_for_each_entry_continue(entity, &dev->entities, list) { for (i = 0; i < entity->bNrInPins; ++i) if (entity->baSourceID[i] == id) return entity; } return NULL; } static struct uvc_streaming *uvc_stream_by_id(struct uvc_device *dev, int id) { struct uvc_streaming *stream; list_for_each_entry(stream, &dev->streams, list) { if (stream->header.bTerminalLink == id) return stream; } return NULL; } /* ------------------------------------------------------------------------ * Descriptors parsing */ static int uvc_parse_format(struct uvc_device *dev, struct uvc_streaming *streaming, struct uvc_format *format, __u32 **intervals, unsigned char *buffer, int buflen) { struct usb_interface *intf = streaming->intf; struct usb_host_interface *alts = intf->cur_altsetting; struct uvc_format_desc *fmtdesc; struct uvc_frame *frame; const unsigned char *start = buffer; unsigned int interval; unsigned int i, n; __u8 ftype; format->type = buffer[2]; format->index = buffer[3]; switch (buffer[2]) { case UVC_VS_FORMAT_UNCOMPRESSED: case UVC_VS_FORMAT_FRAME_BASED: n = buffer[2] == UVC_VS_FORMAT_UNCOMPRESSED ? 27 : 28; if (buflen < n) { uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming " "interface %d FORMAT error\n", dev->udev->devnum, alts->desc.bInterfaceNumber); return -EINVAL; } /* Find the format descriptor from its GUID. */ fmtdesc = uvc_format_by_guid(&buffer[5]); if (fmtdesc !=